In U.S. Pat. No. 4,146,029, Ellinwood suggests a large variety of physiologic sensors all connected by wires to an implanted means for infusing medication. For a variety of reasons, it may not be practical or convenient to connect wires to such sensors. It may not be desirable or practical to connect wires to some implanted sensor (which sensor constitutes one implanted module) because the wires may be damaging to the body, less reliable or may in fact disturb the physiologic measurement.
An article entitled "Long-Term Perfect Glycemic Control With Wearable Artificial Endocrine Pancreas in Depancreatized Dogs", by M. Schichiri et al, at Osaka University Medical School was published in the Abstracts of the International Symposium on Artificial Systems for Insulin Delivery, Assisi, Italy, Sept. 20-23, 1981. This article relates that a glucose sensor, located on the tip of a needle just below the skin attached to an extracorporeal module, was able to accurately measure blood glucose for as long as 7 days. However, Schichiri et al anticipate that the signal from the needle blood glucose sensor will be delivered by an electrical wire to an external pump that delivers insulin. It may, however, be much more advantageous to send a signal from an essentially extracorporeal module (except that the needle sensor is actually beneath the skin) to an implanted insulin release system which could then regulate blood glucose in a closed-loop manner. This system has the advantage that the insulin release system is beneath the skin while the glucose sensor module, being extracorporeal and known to have a limited lifetime, can be readily replaced. An important advantage of the system is that the external portions of the system can be removed during sleep, with the implantable insulin release system going into an open-loop mode to deliver basal insulin during sleep.
In U.S. Pat. No. 3,834,379, entitled "Deterrent for Self-Destructive Actions," Grant suggests a biomedical device system consisting of two extracorporeal modules connected to each other by electrical wires. Described in the Grant invention is one module on the head that senses when the head is struck and another module on the arm that applies an electrical shock for the purpose of conditioning the patient to cease striking his head. The use of electrical wires to interconnect these two extracorporeal modules is disadvantageous because they significantly decrease the reliability of the system, as a result of the fact that the wires get caught on objects and therefore become broken and because such wires are awkward to mount on a patient for extended periods of time. By means of the invention described herein and the system disclosed in the copending Fischell et al application, aversive electrical stimulation to inhibit self-injurious impacts can be accomplished with two extracorporeal modules and without the use of interconnecting wires.
More particularly, in the copending Fischell et al application, an extracorporeal sensing module (typically on the head) senses if that portion of the body is struck. If struck, the sensing module causes a signal to be sent to a remote extracorporeal stimulation module, that produces an aversive electrical shock. The copending Fischell et al application also teaches the use of a multiplicity of extracorporeal sensing modules (e.g. one on the head and one each on each knee and elbow) communicating with an extracorporeal aversive stimulation module. In accordance with the present invention, the sensed signal could, as well, be transmitted to an intracorporeal stimulation module that could be a very effective aversive stimulator by applying an electrical signal directly to a nerve. The present invention furthermore extends beyond the teaching of the copending application by contemplating a multiplicity of intracorporeal modules communicating with each other and/or with a multiplicity of extracorporeal modules.
Although it is well known to have an external programmer communicate with an intracorporeal module, as is the case with cardiac pacemakers that have command and telemetry systems, such external programmers are not carried on the patient who has the implanted pacemaker. The present invention teaches extracorporeal modules that are mounted onto the patient and are in more or less continuing communication with other intra- or extracorporeal modules.